The Senate passed the bill by a 21-14 vote, then the House followed with an 80-55 tally for passage.

However, it is likely to be vetoed by LePage, who proposed and called for the implementation of the grading system in the first place. The result was a bell-curved grading system that gave as many schools A’s and B’s as it did D’s and F’s.

Democrats, led by Sen. Rebecca Millett, D-South Portland, the Senate chairwoman of the Legislature’s Education Committee, assailed the grading system as soon as it was released, arguing that it was too simple to accurately grade Maine schools because of its reliance on attendance and standardized test scores. Millett continued that argument Tuesday during Senate debate.

“We want to know how well Maine schools are preparing students for life after the cap and gown,” said Millett. “This is information that cannot be determined based on test scores alone. … Schools should not be penalized for that which they have no control.”

Millett and others propose creating a more wide-reaching school ranking formula that takes into account test scores, free and reduced lunch rates and the number of students in special education, as well as input from educators and community members. Under Millett’s bill, LD 1540, the formula would be developed through the end of this year by a task force and brought to the Legislature for approval. Democrats have said that the new system wouldn’t likely rely on letter grades but they have not said how schools would be ranked.

Among Democrats’ chief complaints was that the Department of Education developed the A-to-F grading system without input from others.

“If we’re going to help schools improve then we need to have good indicators of how the teachers and administrators in that school are doing,” said Sen. Chris Johnson, D-Somerville. “I strongly support having better measures, ones that not only can be used for shame and political purposes, but which are truly informative about the student and the school in particular.”

Republicans disagreed and said the school grading system is already having the effect LePage said it would: encouraging schools to improve.

“I spoke to an administrator in one of the school districts in my area,” said Sen. Doug Thomas, R-Ripley. “He wasn’t satisfied with the grade his school got, but rather than complain he admitted that there were some areas where he could do better and he said, ‘We will do better. Next time our score will be higher.’”

Sen. Brian Langley, R-Ellsworth, who is the only Republican senator on the Education Committee, agreed.

“Since we’ve started this, the real focus should be on how do we help our schools that are coming up a little bit short?” said Langley.

The Department of Education has already implemented a system to assist low-performing public schools. It includes the sharing of best practices between schools and working directly with schools on specific issues over which they struggle.

LePage proposed earmarking $3 million to improve those schools in his biennial budget proposal, but that money was stripped out of the budget bill during the committee process. The biennial budget passed by the Legislature last week awaits action from LePage.